Freshwater mussels
Illinois Natural History Survey http://www.inhs.uiuc.edu/cbd/main/collections/mollusk.html has great information and photos of freshwater mussels.
Freshwater mussels of Iowa http://www.ag.iastate.edu/centers/wrg/mussels/page4.html
Unio Gallery http://courses.smsu.edu/mcb095f/gallery/ has great information, photos, and video footage of freshwater mussels.
Freshwater mussels of Alabama http://www.dcnr.state.al.us/agfd/musid.html has photos and information about freshwater mussels.
Photos of federally listed freshwater mussels http://nceet.snre.umich.edu/EndSpp/ESimages/ESmollusks.html.
Freshwater mussel anatomy http://www.bio.umass.edu/biology/conn.river/fwmussel.html.
Exotic mussels
Zebra mussel web site http://www.umesc.usgs.gov/invasive_species/zebra_mussels/zm-fastfacts.html
Microorganisms
For more information about microorganisms visit http://commtechlab.msu.edu/sites/dlc-me/zoo/zwp0257.html